This is a Division of application Ser. No. 11/578,520 filed Jun. 1, 2007, which in turn is a PCT of Application No. PCT/FR2005/050240, filed Apr. 14, 2005. The disclosures of the prior applications are hereby incorporated by reference herein in their entirety.
The present invention relates to a structure including an electronic device, e.g. a radio frequency identification device (RFID), in particular for fabricating a security document or a document of value or for making an article secure. The electronic device may enable data to be exchanged without contact.
The term “making an article secure” is used to mean providing an article, e.g. constituted by a packaging device, with an electronic device capable of serving to prevent theft, or to act as authentication or tracing means, for example.
Patent application GB 2 279 907 discloses a smart card made by assembling bottom and top layers with a central structure carrying an electronic device which comprises an integrated circuit and a coil connected to the circuit. In order to make the central structure, the electronic device is sandwiched between polyester layers, each covered on one face in a thermally-activatable adhesive. The central structure is itself sandwiched between bottom and top layers of polyvinyl chloride (PVC). The layers constituting the central structure are assembled with the electronic device and the central structure is assembled with the bottom and top layers during fabrication of the card. Under the action of pressure and temperature, the electronic device is pressed into the adjacent layers, thereby compensating for its thickness, while the various layers are bonding together. That patent application does not describe a preassembled central structure.
U.S. Pat. No. 6,305,609 discloses a smart card made by assembling together bottom and top layers with a central structure carrying an electronic device. The central structure comprises a support film carrying the electronic device which comprises an integrated circuit and a coil connected to the circuit. The device projects from both sides of the support film. The projecting portions are compensated in thickness by a thermoplastic liquid that is cross-linked under UV radiation. The liquid is inserted at the last moment during assembly of the central structure with the above-mentioned bottom and top layers. These layers and the support film are made of thermoplastic material. That type of central structure that presents extra thicknesses requires special equipment for final assembly in the card, or for example between bottom and top layers that are made of fiber, for example.
U.S. Pat. No. 6,233,818 discloses a smart card made by assembling together bottom and top layers with a central structure carrying an electronic device. The central structure comprises a support film of thermoplastic material with a window within which the electronic device is placed, which device comprises a module with an integrated circuit and a copper coil that is connected to the circuit and inserted at the surface of the film using an ultrasound method. The film is made of PVC, polycarbonate (PC), or modified polyethylene terephthalate (PET-G), and is then directly laminatable with printed bottom and top layers to fabricate the smart card using special equipment that generates pressure and temperature.
Such a structure is difficult to handle since the antenna is flush on the structure.
In addition, that type of structure is not adapted to being integrated directly between the cover of a passport and its booklet of sheets, for example, since the book-binding adhesives presently in use are applied in cold and in liquid form.
Patent application WO 00/42569 discloses a label made by depositing the following layers in succession on paper covered in silicone:
a layer of adhesive that can be cross-linked under the effect of UV radiation; a layer of an electrically conductive material forming connection tabs;
a layer of dielectric material;
a layer of a conductive metallic ink for forming an antenna; and
an expandable layer containing a polymeric resin and including a window.
The electronic device is inserted in the window of the expandable layer in contact with the antenna. In that application, there is no preassembled central structure. The expandable layer includes a cavity in the vicinity of the chip to avoid excess thickness. With a label made in that way, it is relatively easy to peel the label from its support after it has been applied thereto, and without leaving evidence of falsification. Finally, such a construction does not serve to hide the electronic device, i.e. the chip and its antenna, when observed using transmitted light.
International application WO 02/089052 describes a passport in which the cover is provided with a radiofrequency identification device.
That cover may comprise a first sheet carrying the radiofrequency device, a second sheet provided with a hole, and a third sheet of paper, the sheets being stuck together and the chip being received in the hole.
International application WO 02/082126 describes a sticky document including an electronic chip connected to an antenna. The antenna is made by printing a conductive ink on an adhesive layer.
The supplier SMARTRAC sells structures known as “prelaminated inlays” comprising layers of polycarbonate or PET, that are to be integrated in a security document. The supplier AONTEC also sells structures known as “prelaminated inlays” for being laminated with layers of a security document, those structures comprising layers of PVC or PC.
Those structures are not entirely satisfactory in terms of security, or in terms of assembly with bottom and top fiber layers.